Piston Valve Pockets

[John Clarke]

Hi again
The Valve pockets on the Pistons of the 616/12 Super ( Stock at 82.5mm) are both inclined / angled, yet only the Exhaust Valve is Inclined. Why is this?
To be confirmed but believe these are Original Mahle Pistons. Also, when replacing the Valve Guides , are they machined in any way to make their removal easier? What is the procedure?
Thanks for any help and comments.
Regards Jay

[C J Murray]

They really only need one pocket...under the exhaust valve only. Original pistons have offset wrist pins to reduce piston slap noise. Therefore the tops are marked to show what part of the piston points to the flywheel. They have to have two pockets to always have a pocket under the exhaust while also maintaining the correct position of the wrist pin offset. JE pistons have the wrist pins centered and so they only have one pocket per piston.